Red alumina color-lake.



pnrran sra'ras PATENT ornron.

CARL THUN, F ELBERFELD, AND PAUL TUST AND PAUL THOMAS CHEWSKI, OF VOH:

WINKEL, NEAR ELLBER-FELD, GERMANY ASSIGNORS 'ro' svn'rnnrrc PATENTS 00.,

me, os'nnw YORK, 1v. Y., A CORPORATION OF NEW YORK.

RED ALUMINA COLOR-LAKE.

Ho Drawing.

Specification of Letters Patent.

Application filed July 15, 1913. Serial No. 779,125.

I To all whom it may concern:

Be it known that We, CARL THUN, PAUL TUs'r, and PAUL. THOMASCHEWSKI, doctors of philosophy, chemists, citizens of the German Empire, residing at respectively, Elberfeld, Vohwinkel, and Vohwinkel, near Elberfeld,

Germany, have invented new, and useful Im-' provements 1n Red Alumina Color-Lakes, of'

which the following is a specification.

We have found the purpurin sulfonic acids having most probably the formula:

Co OH 1 so.s-o.n. c.n on 2 00 OH (4) on Q 1 CO on 2 yield valuable pigments or lakes when treated with alumina as substratum. The new lakes have a valuable clear bluish-red shade and are fast to light.

In order to illustrate the new process more fully the following examples are given, the

parts being by Weight:

Example 1: 100 parts of aluminium sulfate (10 per cent. A1 0 and 1.25 parts of 1.2.4 trioxyanthraquinone 3 sulfonic acid having the formula:

l Lml In...

are dissolved in 1000 parts of hot water and mina hydrate the lake is precipitated with a-solution-of parts of calcined sodium carbonate in 300 parts of water. washed, dried and ground.

Example 2: 1.25 parts of 1.2.4-trioxyan- The lake is filtered ofi,

Patented Mar. 17, 1914.

fonic acid and containing aluminum, said lake being distinguished by its valuable bluish-red shades and its fastness to light, substantially as described.

In testimony whereof We have hereunto set our hands in the scribing Witnesses.

CARL THUN. [L- 8-] PAUL rcsr. [1..s.] PAUL THOMASGHEWSKI. a. 8-]

Witnesses:

HELEN NUFER, ALBERT NU ER- presence of two sub- 

